A factory built, or pre-fabricated, chimney belongs with the fireplace it was specifically designed for; they are not mix-and-match systems. This makes maintenance of both doubly important, because – like cars – models and parts disappear from the market. Unlike cars, however, you cannot slap a different ‘exhaust pipe’ on a factory built firebox.
At some point, a pre-fabricated fireplace system – which includes its chimney, engineered for compatibility with that firebox – wears out. Regular attention to the system extends the life of any fireplace and chimney, but matching bricks are a lot easier to find than the right pre-fab chimney. The financial consequences of inattention to a factory built system can be especially extensive, so its proper care and maintenance is essential.
“A Decorative Heating Appliance”
That is what a pre-fabricated fireplace system is considered to be, and it is important to keep it in mind. Factory built chimneys are not designed to handle the same amount of heat that the flue tiles of masonry chimneys can withstand. Too much heat in the stack can warp the metal or cause separation at the joints.
That has to factor into your choice of woods if that is your fuel, as well as how high you can safely build a fire. It also emphasizes the importance of ensuring that an inserted firebox is of the right type for an existing chimney. A new firebox may allow the generation of more intense heat than the chimney is designed to accept and a chimney fire can be the result.
Once a CSIA certified chimney professional or building inspector has verified the proper installation of compatible parts, yearly cleaning and inspection of the system maintains it. Although creosote accumulation generally occurs more slowly, “fire stops” and screens are more likely to be damaged and blocked. Annual attention by a certified sweep will extend the longevity of the whole system.